Cell Phones: Hands-Free Not Risk-Free

Use of phones while driving cuts attention, response time

TUESDAY, Jan. 28, 2003 (HealthDayNews) -- When you're talking on a hands-free cell phone while driving, your eyes may be focused on what's ahead, but your mind's often elsewhere.

University of Utah researchers report this "inattention blindness" slows a driver's response time and attention, increasing the risk of accidents.

The conclusion may come as a surprise to those who view hands-free cell phones as a safe alternative to hand-held models.

"You find this inattention blindness, which shows that even though your eyes may be looking directly at something, you may fail to see it or not see it in time," says David Strayer, an associate professor of psychology at the University of Utah.

"Just because your eyes are looking at something outside the window of the car, it doesn't mean your brain is going to process it," he adds.

The study appears in the March issue of the Journal of Psychology: Applied. It builds on work by the same researchers in 2001, when they concluded that the use of hands-free and hand-held cell phones impair driving ability equally.

In the new study, Strayer and his fellow researchers found talking on a hands-free cell phone reduced the amount of visual information drivers processed by about 50 percent.

The study focused on 110 University of Utah undergraduate students who participated in four experiments designed to gauge the effect of hands-free cell phone use on driving.

In one experiment, 40 participants operated a high-tech simulator, sitting in the driver's portion modeled after a Ford Crown Victoria. Participants drove a 40-mile stretch of simulated freeway, in light and heavy traffic, with a pace car in front of them.

The same participants drove while talking on a cell phone and while not doing so. While talking on a cell phone, they reacted "sluggishly," tried to compensate by staying farther behind the pace car, and took longer to brake and to accelerate, the researchers say.

Three accidents -- drivers rear-ending the pace car in heavy traffic -- occurred when participants conversed on the cell phones. No accidents happened when they weren't on the phones.

In a test to measure attention to the road, 20 students drove through a simulated city scene where they saw 15 billboards while talking on a cell phone and 15 billboards while not talking on a cell phone. Participants later recognized only about half as many of the signs they encountered when on the cell phone than when they were not.

Other students took the same simulated city drive while researchers tracked their eye movements, and the students looked at the billboards for the same length of time whether on a cell phone or not. Cell phone use made it harder for participants to remember later which billboards they had seen, the researchers say.

Study participants also maneuvered a joystick to track a moving target on a computer screen as words appeared every 10 to 20 seconds. Cell phone users were slower to identify words later.

Rae Tyson, a spokesman for the National Highway Traffic Safety Administration, says the study reaffirms the dangers of driving while talking on a hands-free cell phone.

"It's always been a safety concern for us for the very reasons spelled out in that study," he says. "The fact is that hands-free is not necessarily risk-free.

"Just the degree of concentration it takes to carry on a conversation is enough to distract you from your primary task," Tyson says. He adds that the agency recommends pulling off the road if you need to talk on a cell phone.

Research suggests about 140 million people in the United States subscribe to cell phone service, and 85 percent of them use the phones in cars, says Matt Sundeen, program principal in the transportation unit of the National Conference of State Legislatures.

The potential dangers of using the phones while driving have drawn considerable attention among lawmakers.

New York state has banned hand-held cell phone use while driving, while New Jersey forbids those under 21 with learner's permits to use any cell phones while driving. Other states have imposed restrictions, such as forbidding school bus drivers to talk on cell phones while driving and banning cell phone earphones covering both ears.

More new laws seem likely. This year, 21 states are considering legislation governing cell phone use while driving, Sundeen says.

More information

For more information on driving while talking on cell phones, visit the National Safety Council. The AAA offers these cell phone safety tips.

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